CAYCE, S.C. (AP) — An Amtrak passenger train slammed into a parked freight train in the early-morning darkness Sunday after a thrown switch sent it hurtling down a side track, authorities said. Two Amtrak crew members were killed, and more than 100 people were injured.

It was the third deadly wreck involving Amtrak in less than two months.

The Silver Star, en route from New York to Miami with nearly 150 people aboard, was going an estimated 59 mph when it struck the empty CSX train around 2:45 a.m., Gov. Henry McMaster said.

The crash happened near a switchyard about 10 miles (16 kilometers) south of Columbia where railcars hauling automobiles are loaded and unloaded.

Robert Sumwalt, chairman of the National Transportation Safety Board, said investigators found a switch had been set in a position that forced the Amtrak train off the main track and onto the siding.

He said the question for investigators is why that happened.

Amtrak President Richard Anderson appeared to point the finger at CSX, saying the signal system run by the freight railroad at that spot was down at the time, and CSX dispatchers were manually routing trains. The NTSB said it was working to confirm that.

CSX issued a statement expressing condolences but said nothing about the cause of the accident.

Sumwalt said that positive train control — a GPS-based safety system that can automatically slow or stop trains — could have prevented the accident.

“That’s what it’s designed to do,” he said, referring to technology that regulators have been pressing for for decades with mixed success.

Investigators recovered a camera from the front of the Amtrak train and were looking for the data recorders from the two trains.

The switch that triggered the crash was padlocked in position, which conductors are supposed to do when they move a train from one line to another, Sumwalt said.

The force of the crash dislodged a seat and knocked it onto passenger Tronia Dorsey’s legs, said her son, Andre Neblett, who spoke with her. The 43-year-old woman, who escaped with minor scratches and bruises, described a terrifying scene inside the dark compartment, with people screaming and babies wailing, he said.

“It was chaos,” Andre Neblett said after driving in from North Carolina to retrieve his mother’s suitcase from a Red Cross shelter. “She said she was just waiting on somebody to get to her.”

The conductor and engineer aboard the Amtrak locomotive were killed. And 116 people were taken to four hospitals, according to the governor.

At least three patients were hospitalized in critical or serious condition, with nearly all the rest treated for minor injuries such as cuts, bruises and whiplash, authorities said.

Palmetto Health emergency room doctor Eric Brown said so many passengers were hurt that they were brought in on two buses, and a tent that had been set up as a waiting room to keep people separate from flu patients was turned into a triage area.

The locomotives of both trains were left crumpled, the Amtrak engine on its side. One car in the middle of the Amtrak train was snapped in half, forming a V off to one side of the tracks.

“It’s a horrible thing to see, to understand the force involved,” the governor said after touring the scene.

In a statement, Amtrak said that it was “deeply saddened” by the deaths and added that it was cooperating fully with the NTSB, as did CSX. But Amtrak also also said CSX maintains all the tracks and signals where the accident happened and controls access to the sidings and yards.

Amtrak’s Anderson said the crash shows the importance of making sure that positive train control is installed on every train and track in the nation by the government’s year-end deadline.

The system is in place in the Northeast, but railroads that operate tracks used by Amtrak elsewhere in the U.S. have gotten extensions to the deadlines.

Amtrak officials gathered up luggage and other belongings and within hours put passengers aboard buses to their destinations. Many of them were asleep when the crash happened.

Before being sent on their way, those who were not hurt were taken to a shelter set up at a middle school, and local businesses provided coffee and breakfast.

“We know they are shaken up quite a bit. We know this is like nothing else they have ever been through. So we wanted to get them out of the cold, get them out of the weather — get them to a warm place,” sheriff’s spokesman Adam Myrick said.

Lexington County Coroner Margaret Fisher’s voice caught as she released the names of the dead.

“Any time you have anything that happens like that, you expect more fatalities. But God blessed us, and we only had the two,” Fisher said.

On Wednesday, a chartered Amtrak train carrying Republican members of Congress to a strategy retreat slammed into a garbage truck at a crossing in rural Virginia, killing one person in the truck and injuring six others.

And on Dec. 18, an Amtrak train ran off the rails along a curve during its inaugural run on a route south of Tacoma, Washington, killing three people and injuring dozens. It was going nearly 80 mph, more than twice the speed limit.

After the latest crash, Democratic Sen. Richard Blumenthal of Connecticut said the nation’s railroads must be made safer, declaring, “Business as usual must end.” He said proven technology, including positive train control, cannot continue to be delayed.

The latest wreck again raised criticism about the safety culture of the nation’s passenger railway.

With the string of crashes, “it’s becoming almost like an epidemic for Amtrak,” said Najmedin Meshkati, a University of Southern California engineering professor who has studied positive train control.

The worst rail tragedy in recent South Carolina history took place in 2005 when a freight engineer parked a train on a side track near a textile mill in Graniteville and forgot to flip the switch back to keep trains on the main track.

A freight train passing through went barreling down the side track and slammed into the parked train, killing nine people, most of them millworkers choked by chorine gas that leaked from a damaged tanker car.

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Associated Press writer Jeffrey Collins in Columbia, South Carolina, contributed to this report.

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